A common way of modifying the lift characteristics of an airfoil for low speed operation is to use leading edge devices which either pivot or slide outwardly from the leading edge of the airfoil to a deployed position. With many such devices, there is a problem that during deployment there is an interruption of smooth airflow over the upper surface of the airfoil. Also, many such devices are not able to be deployed to intermediate positions while maintaining the proper flow of air over the airfoil.
Accordingly, there have appeared in the prior art various devices to vary the shape of the airfoil itself in a manner to vary the camber of the leading edge. Variable camber leading edges are particularly desirable in solving the airfoil stall problem for small, thin, swept-back wings which have good cruise performance, but require high lift devices to make their low speed performance acceptable. However, there is a problem of installing such variable camber leading edge devices on such wings since these thin wings have the least space available in which to house such devices.
Accordingly, it is an object of the present invention to provide a device to vary the camber of an airfoil, and particularly such a device used as a variable camber leading edge assembly. It is a more particular object to provide such an assembly with a flexible upper skin panel which is moved from a cruise position to a more curved high lift position, with the flexible panel having a desired aerodynamic contour throughout its path of travel between the upper cruise position and the downwardly deflected position, with the assembly being relatively compact, and with the major part of the aerodynamic load on the assembly being transmitted into the support structure so as to relieve loading on the drive mechanism of the assembly.